Trestle



1No Model.)

T. -P. MADDOX.v

No. 264,310. Patented s611112, 1882.

UNITED STATES PATENT OFFICE.

THOMAS P. MADDOX, OF ST. LOUIS, MISSOURI.

TRESTLE.

SPECIFICATION forming part of Letters Patent No. 264,310, dated September 12, 1882.

Application sied June s, 1882. (No model.)

To all whom it may concern VBe it known that I, THOMAS P. MADDOX, of St. Louis, Missouri, have made a new and useful Improvement in Trestles, of which the following is a full, clear, and exact description, reference being had to the annexed drawing, making part of this specification, in which a trestle having the improvement is shown in perspective.

The present invention is an improvement in trestles having extension-tops, and the improvelnent relates taille means for bracing the top when extended.

Referring to the drawing, -A represents a trestle ot' the kind under consideration, having the topa, and legs a a a2 a2.

B represents the extension-top. It is attached to and supported by the rackbars O C, which in turn work vertically upward and downward through the top a.

D represents a shaft turning in suitable bearings in the trestle, and provided with pinions E E, which engage with the rack-bars O O. The shaft is also supplied with the cranks F F and the ratchets G G. Pawls gg enga-ge with the ratch'ets G G. B v rotating the shaft D the extension-top Bis raised to and lowered ilrom the top a. v

H H represent dogs attached to and turning with the shaft h. The shaft h turns in the bearing h h', and it is suitably shaped at the end or provided with a handle, to enable it to be readily rotated in its bearings h h', and thereby throw the dogs H H into or out oi' enployed, one at each end of the trestle. Each arm 4o is in two parts, I and I', the part I beingjointed at i to theleg a', the two parts I lbeing jointed together at t" and the part I beingjointed to the extension-top B at 2. The part I, as the extension-top is raised and lowered, turns on thejoint i upward and downward past the leg a2. That portion ot' the part I that comes opposite the leg a2 has a series, t3, of perforations. The leg a2 has a series, a3, of perforations. When it is desired to brace the extension-top at any desired point of elevation a pin, J, is passed through one of the perforations i3 into the opposite perforation in the series a3. The part I of the arm then operates as a brace to give lateral support to the top B.

1. The-trestle A, having the extension-top B and the braces I l', substantially as described.

2. The combination of the top a, the legs c a a2 a?, the rack-bars O O, the shaft D, thepinions E E, the arms I I', and the pin J, snb stantially as described.

T. P. MADDOX.

Witnesses:

G. D. MOODY, CHARLES PIGKLEs. 

